The present invention relates to a power source circuit, and more particularly to a power source circuit constructed through utilization of a semiconductor element to maintain a constant DC voltage and to have a high AC output impedance so that an AC signal may be superimposed on the output line of the power source.
A conventional power source circuit of the type which comprises a choke coil having a DC resistance, has a defect such that the DC voltage across the output lines fluctuates with the value of the DC current flowing therethrough.